function fval = int_2nd_price(L, B, a_b, a_s, EPS_L_BOUND, EPS_H_BOUND, S_PARAM, M_PARAM, THETA, DELTA, CHI, tau_k)

sig = S_PARAM;
mu  = M_PARAM;
f   = @(x, a) 1 ./ (x * sig * sqrt(2 * 3.14159265359))...
    .* exp(- (log(x) - mu - a).^2 / 2 / sig^2)...
    .* (x >= EPS_L_BOUND) .* (x <= EPS_H_BOUND);
int_method = 'auto';
Rel_Tol    = 1e-5;
Abs_Tol    = 1e-6;


fun_l_bound      = @(a) EPS_L_BOUND; % lower bound
fun_h_bound      = @(a) EPS_H_BOUND; % upper bound
 
fval = 2 * integral2(@(eps_t, eps) ((1 - tau_k) * B...
                * ((1 - THETA) * eps + THETA * eps_t) + 1 - DELTA) .* f(eps_t, a_s) .* f(eps, a_b),...
                fun_l_bound(a_s), fun_h_bound(a_s), @(eps_t)eps_t, fun_h_bound(a_b), 'method', int_method);
            
end